Bits and Bytes.
17/2 PartV Bits and Bytes
Chapter 1 7 Hardware and Peripherals
17.1 ... Memory
The microprocessor was a significant key to
lowering the cost of the personal computer. However the
other key and an egually important one was low-cost
semiconductor memory. Semiconductor memory started
replacing magnetic core memory around 1967.
Their are two types of semiconductor Random Access
Memory (RAM) . Dynamic RAM (DRAM) reguires periodic
refresh of the memory contents and Static RAM (SRAM)
retains the contents without refresh. Both types of RAM
loose their contents when the power is turned off. Read
only memory (ROM) retains its contents once it is
programmed, even when the power is turned off.
The first commercial IK metal oxide semiconductor
DRAM was the Intel 1103 released in October 1970. This
chip had a pivotal role in undercutting the price and
replacement of core memory. Intel continued to improve
DRAM capacities with the release of the 4K 2107 chip in
1972 and the 16K 2117 chip in 1977. However, competitive
challenges from Japanese companies, would have a
significant impact on Intel and other North American
producers of memory chips .
Japan decided to make a strategic investment in
the semiconductor memory industry around in the late
1970' s. The effect of this was the first open market
release of a 64K DRAM chip by Fujitsu Limited in 1979,
and introduction of the first 1-megabit DRAM chip by the
Toshiba Corporation in 1985. A number of other factors
contributed to the dominance of Japanese manufacturers
in the 1980' s. Some of these were: a cooperative
relationship between various companies in the Japanese
industry, illegal use of U.S. technology, superior
guality that contributed to lower costs and a
significant investment in new facilities to produce
memory chips. This resulted in a price war by the
Japanese producers to increase their market share
through the early 1980' s. By 1985 the market situation
17/4 PartV Bits and Bytes
for North American producers had so deteriorated, that
the U.S. Government accused Japan of unfair trading
practices and filed an antidumping complaint against the
Japanese manufacturers. A semiconductor agreement was
signed by the governments of Japan and the United States
in 198 6. However, by this time it had adversely affected
many U.S. companies such as the Intel Corporation that
had already decided to withdraw from the DRAM market.
The company also withdrew from the EPROM chip market in
Erasable Programmable Read-Only Memory (EPROM)
was invented by Dov Frohman at Intel. The memory
contents can be programmed then erased by exposing the
chip to ultraviolet light. Intel released the 2K-bit
1702 EPROM chip in September 1971. This alterable
storage medium provided a low cost way to store
microcomputer programs and became a successful and
extremely profitable product for Intel until the mid
Flash memory was developed by Toshiba. It
provided the non- volatility of EPROM but the memory
could be erased electrically. Electrically Erasable
Programmable Read-Only Memory (EEPROM) was developed by
National Cash Register (NCR) and Westinghouse companies .
17.2 ... Storage Devices
Paper tape was one of the earliest forms of
storage for personal computing. However it normally
required a teletype machine for input/output that was
too expensive for the average user.
Another early storage medium for personal
computers was the magnetic audio cassette tape and the
subsequent digital data cassette. Information Terminals
Corporation (ITC) was the first producer of high quality
data cassettes. The company was founded by J. Reid
Anderson in April 1969. Anderson had previously
developed acoustic-coupler modems and a prototype for a
"smart" computer display terminal. During the
development of the computer display terminal, Anderson
Hardware and Peripherals 17/5
determined that audio tape cassettes were not a
sufficiently reliable storage medium for recording
digital data. The audio cassettes did not have a uniform
magnetic coating or a precise cassette body that
resulted in "dropouts" or lost data. This resulted in
the development of a high guality, precision data
cassette that ITC started producing in 1970. The company
became the dominant supplier of digital data cassettes
in the 1970' s. ITC introduced a mini cassette for
portable data processors and a guarter-inch data
cartridge in 1975. A new superior coating media for
tapes and disks named Verbatim, was announced in
February 1977. The company changed its name to Verbatim
Corporation in late 1978, and went public in February
The 3M company introduced guarter-inch tape drive
media in 1971. The capacity of these early drives was
only 30 megabytes.
Jerry Ogdin developed the concept of using two
tones on magnetic tape to represent digital data. This
was implemented in a Popular Electronics construction
article with the name of HITS (Hobbyists' Interchange
Tape System) in September 1975. It was inexpensive and
was adapted by many manufacturers . Initially each
company had their own formatting standards. However in
November 1975 BYTE magazine organized a meeting in
Kansas City, Missouri of interested companies. The
companies agreed to a format that became known as the
"Kansas City Standard." This standard facilitated the
exchange and use of magnetic tapes on different systems.
The Beginning at IBM
Hard disk drive technology was developed by IBM
in the 1950's as described in Section 1.3. The first
Winchester hard disk drive was announced by IBM in March
1973 as the Model 3340 Disk Storage Unit. It was
developed as a low-cost drive for small to intermediate
computer systems. The term Winchester was used by the
engineers due to the storage capacity characteristics
and similarities to the name of a popular rifle as
17/6 PartV Bits and Bytes
described in Section 20.4. A principal in the
development was Kenneth E. Haughton who had assumed
responsibility for the project in 1969. The drive
assembly used a removable sealed cartridge with 14-inch
diameter disks and was available in 35 and 70 megabyte
Floppy disk drives were developed at IBM
laboratories by David L. Noble during the period of 1967
to 1971. They were initially developed by IBM as a means
of storing and shipping microcode for Initial Control
Program Load (ICPL) software programs on mainframe
computers. The jacket enclosing the diskette was
developed to protect the disk during handling and
The initial eight inch diameter read only units
had a product designation of 23FD, a code name of Minnow
and shipped in 1971. The diskette on the read only units
rotated at 90 revolutions per minute and data was
recorded on one side only. The diskette capacity was
81,664 bytes on 32 tracks which were hard sectored with
eight holes around the outer edge of the disk.
The eight inch diameter read-write units had a
product designation of 33FD, a code name of Igar and
shipped in 1973. The diskette on the read-write drive
units rotated at 360 revolutions per minute, had a
capacity of 242,944 bytes on 77 tracks which was
recorded on one side only and used magnetic soft
sectoring (no sector holes) . The 33FD diskette drive was
a success and was used in data entry products which
started to replace IBM card systems .
In 1976 the 43FD unit was shipped with data being
recorded on both sides and capacity increased to 568,320
bytes on 154 tracks. In 1977 the 53FD double-density
unit was shipped with capacity increased to 1,212,416
IBM's research and development activities created
the Winchester hard disk drives and the floppy disk
drives. However other companies entered the market to
compete with IBM products and to provide disk drives for
other computer systems . Some of these manufacturers were
Control Data Corporation (CDC), Conner Peripherals,
Hardware and Peripherals 17/7
Maxtor, Micropolis Corporation, MiniScribe, Quantum
Corporation, Seagate Technology, Shugart Associates and
Western Digital Corporation. In the mid 1970' s, hard
disk drives were not suitable for use with
microcomputers due to their large size and high cost.
However by 1976, inexpensive floppy disk drives became
available for personal computers.
Floppy Disk Drives
Alan F. Shugart joined IBM as a customer engineer
in 1951. After a number of positions related to memory
and storage technology he became manager for direct
access storage products. Shugart left IBM in 1969 to
become manager of storage products at Memorex. In 1973
Shugart left Memorex and with Finis F. Connor and Donald
J. Massaro founded Shugart Associates. The company
announced the SA-900 8-inch floppy diskette drive that
retailed for $500 in the summer of 1973. After two years
Shugart had a dispute regarding capitalization of the
company and left. Shugart Associates announced the SA-
400 5.25-inch minifloppy disk drive for $390 in December
1976. The drive used a single-sided single-density
floppy disk with a capacity of 110 kilobytes. Shugart
Associates was acquired by Xerox Corporation in 1977.
However it was not profitable and resulted in Xerox
terminating Shugart operations in 1985.
The first advertisement for a microcomputer
floppy disk drive in the Byte magazine appeared in the
August 1976 issue. The eight inch drive is described as
"iCOM's Frugal Floppy. At $995, your microprocessors
best friend." It was produced by iCOM Microperipherals
that was a division of the Pertec Computer Corporation.
Then in the February 1977 issue of Byte, iCOM advertised
a 5.25-inch Microfloppy disk drive system for $1,095.
North Star Computers, was another early
manufacturer of floppy disk drives for MITS Altair and
compatible microcomputers. The company advertised the
Micro-Disk System (MDS) in the January 1977 issue of
Byte magazine. The unit used a Shugart SA-400 mini
floppy disk drive and sold for $599 as a kit, or $699
17/8 PartV Bits and Bytes
Reference Section 5.5 for information on the
Apple Disk II floppy disk drive introduced by Apple
Computer in 1978. In the late 1970' s, other companies
such as Alps Electric Company of Japan (who supplied
Apple Computer) , Sony Corporation and Tandon Corporation
entered the floppy disk drive market. During 1982,
various Japanese manufacturers offered half-height 5.25
inch floppy disk drives.
Microfloppy disk drives were introduced in the
early 1980' s for portable computers and to provide a
more durable diskette and a less expensive drive
assembly. The term floppy was not accurate as the disk
was contained in a hard-shell cartridge. It also
included an automatic shutter that closed over the
recording surface when it was removed from the drive .
Initially there were different incompatible disk sizes.
Companies such as Hitachi introduced a 3.0 inch drive,
Seagate supported a 3.25 inch dive, Sony and Shugart a
3.5 inch drive, Canon a 3.8 inch drive and IBM a 4.0
inch drive. This resulted in the Microfloppy Industry
Committee (MIC) being formed in May 1982 to reach a
consensus on a common configuration standard. In
September a 3.5 inch system was proposed. Sony became a
dominant supplier of 3.5 inch disk drives in 1983. The
initial Sony disk drive had a storage capacity of 438
kilobytes that was subseguently increased to 1 megabyte
(720 kilobytes formatted) . Early applications of the 3.5
inch drive were in the Hewlett-Packard HP-150 computer
and the Apple Macintosh computer.
Hard Disk Drives
Hard disk drive technology changed significantly
in the years following its initial development by IBM.
The storage capacity, access time and physical size have
been dramatically improved. The original 14-inch
diameter disk was reduced to 8-inches in 1978, then to
5.25-inches in 1980, to 3.5-inches in 1984 and to 2.5-
inches in 1989.
The first Winchester 8-inch hard disk drive was
introduced by Shugart Associates in 1978. Alan Shugart
and Finis F. Conner who had been cofounders of Shugart
Associates founded Shugart Technology in 1979. A major
Hardware and Peripherals 17/9
investment was made in the new company by the Dysan
Corporation, a disk manufacturer. Shortly after the
company name was changed to Seagate Technology, Inc. The
first Winchester 5.25-inch hard disk drive with a
storage capacity of 10 megabytes was announced in June
198 0. Conner left Seagate and founded his own disk drive
company called Conner Peripherals, Inc. in 1985. Seagate
Technology became a dominant supplier of disk drives
when it acguired the disk operations of Control Data
Corporation in 1989. In early 1996, Seagate purchased
Conner Peripherals and became the largest U.S.
manufacturer of hard disk drives.
David Brown, James Patterson and others founded
the Quantum Corporation in 1980. The companies first 8-
inch hard disk drive was produced in early 1981 and a
3.5-inch hard disk drive was introduced in 1988. The
company is now the second largest manufacturer of hard
disk drives .
Western Digital Corporation was founded as a
manufacturer of calculators and semiconductors in 1970.
In the mid 1980' s, the company reorganized and changed
product lines to concentrate on storage devices. The
company acguired the disk drive operations of Tandon
Corporation in 1988. Western Digital is now the third
largest U.S. manufacturer of hard disk drives.
Apple Computer's first mass storage system called
the ProFile was introduced in September 1981 for the
Apple III computer. The unit used Winchester technology,
had a 5 megabyte storage capacity and was priced at
$3,495. The hard drive within the ProFile unit was the
ST-506, a 5.25-inch drive manufactured by Seagate
Technology. The drive had a built-in power supply and a
Z-8 based controller.
Compact disk (CD) technology was developed as a
joint effort by N.V. Philips of the Netherlands and Sony
Corporation of Japan in 1976. This led to a number of
specifications to define the disk format standards for
the various types of media by the early 1980' s (see
Section 20.3). Compact Disk - Read Only Memory (CD-ROM)
drives with a capacity of 550 megabytes were introduced
17/10 PartV Bits and Bytes
in the USA in the fall of 1984. However with an initial
price of over $2,000 they were expensive. High price,
lack of applications and a need for format recording
standards inhibited the early proliferation of the
David Bailey and David Norton founded the Iomega
Corporation in 1980. Iomega introduced the Bernoulli
removable disk drive with a storage capacity of 44
megabytes for personal computers in 1983. It is also
known as a Bernoulli Box and features capacity
comparable to a hard disk and a removable assembly for
The name Bernoulli is from an eighteenth century
mathematician Daniel Bernoulli who described the air
dynamics utilized in the drive. The concept enables an
extremely close read/write head to disk relationship but
also a more tolerant protection from drive-head crashes.
A 100 megabytes Zip drive was introduced in 1995
and became guite popular as a removable high capacity
disk storage system. The larger Jaz drive was introduced
later, but had a number of problems.
The first 12 inch diameter optical drives with
Write Once, Read Many Times (WORM) recording
capabilities were introduced in 1983. This was followed
by 5.25 inch drives that were introduced in 1985. The
principal feature of the optical drive is its extremely
large storage capacity, up to 1 gigabyte. The NeXT
computer was one of the earliest applications of the
optical disk drive.
17.3 ... Input/Output Devices
Prior to the introduction of low cost monitors,
printers and storage devices the teleprinter was a
common computer input/output device. The teleprinter had
an alphanumeric keyboard for input and a character
printer to produce hardcopy output. It could also
Hardware and Peripherals 17/11
include a communications interface, magnetic tape unit
or a paper tape punch and reader for data storage
input/output. The teleprinter was often loosely referred
to as a "Teletype" due to the dominant position of the
Teletype Corporation in the market.
The other significant supplier of teleprinters
was IBM. The market was generally divided between
Teletype and IBM compatible teleprinters.
The Teletype Corporation produced many different
teleprinter models, however popular units included the
Models 33 and 35 which were announced in 1963. Three
versions of each model were produced with different
system designs. The ASR-33 (Automatic Send-Receive)
version was priced from $755 to $2,000 depending on the
configuration. The printer speed was 10 characters per
For the personal computer user a new machine was
not only expensive but difficult to obtain. The use of
used or rebuilt machines at more affordable prices was
17.4 ... Displays
The September 1972 issue of Electronic Design had
an article describing how to build a circuit that could
display 1,024 ASCII characters on a TV set.
Don Lancaster was an electrical engineer who in
the late 1960's started writing articles for Popular
Electronics and Radio-Electronics magazines. One of
Lancaster's articles described a project on how to build
a decimal counting unit. Then in the September 1973
issue of Radio-Electronics Lancaster had an article
entitled "TV Typewriter"  that described how the
computer could be connected to a television set. A TVT-1
prototype was built by Lancaster and sold as a kit for
$120 in 1973. The unit could store up to 1,024
characters and display 16 lines of 32 characters. The
unit had text editing capabilities and construction
details were available for $2 .
17/12 PartV Bits and Bytes
The VDM-1 Video Display Terminal was a prototype
only that was developed by Lee Felsenstein in 1974. It
was the first video terminal to be used interactively
with a personal computer.
In 1972 the IBM 3270 Information Display system
was announced. This provided improved speed and silence
of operation. It also facilitated interaction between
the user and the computer.
Lear Siegler Inc. (LSI) was an early supplier of
"glass teletype" terminals after introducing the LSI
ADM-1 terminal at a price of $1,500. Another major
supplier of microcomputer monitors was Amdek, founded by
Go Sugiura in 1977.
17.5 ... Printers
The initial development of wire matrix printing
was by Reynold B. Johnson at IBM. The initial concept
used a 5 by 7 array of wires to form a character. It was
introduced with the Type 26 keypunch in 1949.
In 1954 Burroughs Corporation announced a wire
printer producing 100 character lines printing at 1000
lines per minute. In 1955 IBM announced two high speed
printers capable of printing 1000 lines per minute.
These high speed wire printers experienced numerous
problems and were not successful.
In 1969 IBM introduced the Model 2213 seven-wire
printer. This printer was unidirectional and printed at
a rate of 66 characters per second.
Centronics Data Computer Corporation was founded
by Robert Howard as a computer systems company. The
company designed a dot matrix printer called the Model
101 which was introduced in the spring of 1970. It had a
speed of 165 CPS (Characters Per Second) using a 5 by 7
matrix and sold for $2,995. The Micro-1 printer with a
print speed of 240 CPS and a price of $595 was released
in 1977. Then in 1979, the company introduced the
Centronics 700 series that included the Model 779 that
Hardware and Peripherals 17/13
was priced at less than $1,000. Centronics was a
dominant supplier of dot matrix printers in the 1970' s.
Epson was one of the initial developers of low
cost dot matrix printer technology. Epson's technology
evolved from a printing device developed to print
results from Seiko's quartz watch which was introduced
at the 1964 Olympics in Japan. Subsequently a miniature
printing device called the EP-101 was marketed by Seiko.
In 1975 Seiko established a subsidiary which they
named Epson America, Inc. It was established to market
and distribute microcomputer products worldwide. The
name Epson was derived from the "son" of the EP-101
printer. Initially the company sold component parts to
original equipment manufacturers (OEM's) who
manufactured printers under their own brand name. Epson
released its own dot-matrix printer, the TX-80 in 1978.
This was the first low cost printer for microcomputers
and was an immediate success.
The MX series of printers were introduced in
1980. This series was sold for the IBM Personal Computer
under an OEM agreement. Subsequently Epson has developed
an extensive range of printers using various
Reference Section 11.7 for Epson computer
The IBM ProPrinter was introduced in the spring
of 1985. It had a speed of 200 CPS, NLQ (Near Letter
Quality) and was priced at $549.
Other Printers and Developments
In the late 1970 's additional wires were added to
the printhead to improve the resolution of dot matrix
printers. The early 7-wire heads were changed to include
9, 12, 14, 18 and by the early 1980 's the 24-wire head
was introduced. These improvements have provided what is
called "Near Letter Quality" (NLQ) and "Letter Quality"
(LQ) printed output.
17/14 PartV Bits and Bytes
Color dot matrix printers became available in
the late 1970' s. A four color ribbon was used with
overprinting to obtain various colors .
C.Itoh Electronics (CIE) , Inc. was established in
December of 1973. It was an early supplier of low cost
printers for personal computers. A low cost, 80-column
desktop printer was developed in June 1976. The Apple
Computer company marketed the C.Itoh printer under the
name of ImageWriter. Apple introduced the ImageWriter in
December 1983 at a price of $675.
In the 1980 ' s many other companies started
competing in the low cost dot matrix printer market.
Some of these were NEC, Okidata and TEC. Currently there
is a rapid shift in the market to move from wire matrix
printers to ink jet and laser type printers. This is due
to the noise, print guality and print speed of the wire
matrix printer. Also the decreasing cost of ink jet and
laser printers is a significant factor.
Ink jet printing technology has evolved from a
long history of development. However during the
1960/70 ' s research and development accelerated. In 1976
IBM introduced the Model 6640 continuous ink jet printer
which set new standards for print guality.
Canon Inc., a Japanese camera company founded in
the 1930' s, introduced what they called "Bubble Jet"
concept of printing in 1978. Then starting in 1978
Hewlett-Packard developed a thermal drop-on-demand
concept of printing. Color printing capabilities were
introduced in the 1980 's.
The ThinkJet printer was introduced by Hewlett-
Packard in 1984. The printer used a disposable printhead
with twelve individually controlled chambers that
expelled drops of ink from the nozzle. The printer had a
speed of 150 CPS with a 11 by 12 dot character and a
resolution of 96 dots per inch. The printer ink had some
limitations on the type of paper that could be used. The
price of the ThinkJet printer was $495.
Hardware and Peripherals 17/15
Laser printing technology evolved from Chester
Charlson's electrophotographic inventions in 1938. It
was further developed as a copying technology at Haloid
Corporation which became Xerox Corporation in 1961.
Electrophotographic printing is a complex process
involving six steps: Charge of a photoconductor (PC)
surface, exposure of the PC surface to a light pattern
of the print image, movement of the toner to the
appropriately charged areas of the PC surface, transfer
of the developed image to a sheet of paper, fusing the
transferred image to the paper and finally cleaning the
PC surface in preparation for the next printing. Most
electrophotographic printers use either a gas or diode
laser printhead to scan the PC surface. Typical
resolutions for laser printers are from 240 to over 800
dots per inch.
The first laser printer was developed by Gary
Starkweather at Xerox PARC in 1971. Starkweather
modified a Xerox 7000 copier and named the machine
"SLOT," an acronym for Scanned Laser Output Terminal.
The digital control system and character generator for
the printer were developed by Butler Lampson and Ronald
Rider in 1972. The combined efforts resulted in a
printer named EARS (Ethernet, Alto, Research character
generator, Scanned laser output terminal) . The EARS
printer was used with the Alto computer system network
and subseguently became the Xerox 9700 laser printing
An inexpensive laser printer was introduced by
Canon in 1983. The Canon LPB-CX had a resolution of 300
by 300 dots per inch and a operator changeable
disposable cartridge. The Canon engine was sold to
Hewlett-Packard and Apple Computer. The engine includes
the laser diode, lens and mirror system, photosensitive
roller, toner cartridge and paper handler. The Hewlett-
Packard printer was named the HP LaserJet and was priced
at $2,500. The Apple Computer printer was named the
LaserWriter and was priced at $6,000. Hewlett-Packard
subseguently became a dominant supplier of laser
17/16 PartV Bits and Bytes
Burrell Smith was a principal in the development
of the Apple LaserWriter printer. The printer was
developed for the Macintosh computer and included a
Motorola MC68020 microprocessor. The LaserWriter Plus
was introduced in January 198 6 and the LaserWriter II
family of printers in January 1988.
The concept of thermal printing was developed
during the 1960/70 's using special sensitive paper.
Thermal wax transfer printers were introduced by
Brother, Toshiba and others in 1982. A resistive ribbon
thermal transfer printer was introduced by IBM in 1983.
17.6 ... Peripheral Cards
Manufacturers developed many peripheral or add-on
cards for various personal computers. These add-on cards
extended and enhanced personal computer capabilities
beyond those envisioned by the computer manufacturers .
The following is representative of some of the more
significant cards .
Sim Wong Hoo, Chay Kwong Soon and Ng Kai Wa
founded the Singapore company Creative Technology Ltd.,
in 1981. The company started by producing Apple II and
IBM PC clones. Subseguently the focus was changed from
clones to peripherals with the introduction of the Sound
Blaster audio card in 198 9. The company is a world
leader in the manufacture of sound cards and multimedia
accessories. Creative Labs, Inc., is a wholly-owned U.S.
subsidiary and Creative Technology became a public
company in 1992 .
Cromemco was founded by two Stanford University
professors, Harry Garland and Roger Melen in 1975. The
first product was an add-on board called "Bytesaver" for
the MITS Altair 8800 microcomputer. The board had a 2704
EPROM memory chip that could be programmed to load a
monitor program to simplify the startup or "booting" of
Hardware and Peripherals 17/17
the computer. A kit cost $195 or $295 assembled. The
second board produced by Cromemco was called the "TV
Dazzler" and enabled the microcomputer to be connected
to a color television set. The board provided a 128-by-
128 pixel display. A software program called
Kaleidoscope provided an impressive demonstration of the
board capabilities. A kit cost $215 or $350 assembled.
In October 1976 the company released a Zilog Z-80 board
for the MITS Altair 8800 microcomputer. The Z-80
microprocessor was faster and had more extensive
instruction set. The Z-80 board cost $195 as a kit or
Microsoft conceived the concept of an add-on card
that would enable their software to run on an Apple II
computer. The Apple II computer used a 6502
microprocessor, but most of Microsoft's software had
been developed for the Intel series of microprocessors
and the CP/M operating system. With the increasing sales
of Apple II computers, this segment of the software
market was growing.
Microsoft had Tim Paterson of Seattle Computer
Products develop what became the Z-80 SoftCard.
Microsoft announced the Z-80 SoftCard with a price of
$399 in March 1980. Included with the card was the CP/M
operating system from Digital Research and two versions
of BASIC: MBASIC (which was compatible with Microsoft
BASIC-80) and GBASIC with high resolution graphic
enhancements. The card was an immediate success.
The RamCard was released around 1981/82 for the
Apple II Plus computer to extend the memory by 16K to
64K bytes. This additional memory allowed the computer
to run CP/M applications that reguired 64K bytes.
Processor Technology Corporation was founded by
Robert Marsh and Gary Ingram in April 1975. The first
product was a 4K static RAM memory expansion board for
the MITS Altair 8800 microcomputer. This computer only
had 25 6 bytes of memory in the standard unit and the 4K
memory board produced by MITS was not reliable. The
17/18 PartV Bits and Bytes
memory board was first advertised at the Homebrew
Computer Club in April 1975 and the first order was from
Cromemco. It cost $218 as a kit or $280 assembled. A 2K
memory board was also available. The company also made
other boards for the S-100 bus such as a 2K ROM Board, a
3P+S (parallel/serial) board, VDM-1 (Video Display
Module) board designed by Lee Felsenstein and an
improved motherboard for the Altair 8800.
Seattle Computer Products
Rod Brock owned Seattle Computer Products, Inc.,
that supplied memory cards for the S-100 bus computers
around 1978. In late 1978 Tim Paterson, an employee of
the company started developing a card using the new
Intel 8086 microprocessor. The first prototype card was
completed in May 1979. It was then demonstrated using
the new Microsoft 8086 BASIC interpreter at the June
1979 National Computer Conference in New York City.
Production units shipped in November 1979.
Tim Paterson also developed the operating system
called QDOS for the CPU card in 1980 (see Section 13.1).
This operating system later became MS-DOS.
Other Early Manufacturers
Robert Metcalfe, Greg Shaw and Howard Charney
founded 3Com Corporation in 1979. 3Com is an acronym for
the three corn's in computer, communication and
compatibility. The company's main product is
communication interface hardware for computer networks .
Metcalfe had previously been a principal in the
development of the Ethernet communications software at
Xerox PARC. 3Com became a public company in 198 4, and
acquired U.S. Robotics Corporation in 1997.
Applied Engineering released the Transwarp
accelerator card which more than tripled the speed of
the Apple lie was released in January 198 6. In November
198 7 the PC Transporter card was introduced to run MS-
DOS programs on an Apple II computer.
The Hercules Card is a display adapter card
developed by Hercules Computer Technology to display
high resolution text.
Hardware and Peripherals 17/19
North Star Computers advertised in the January
1977 issue of Byte magazine, a FPB Model A floating-
point board to provide faster mathematical calculations .
The board sold for $359 as a kit or $499 assembled. They
also developed cassette tape and floppy disk interface
Howard Fulmer founded Parasitic Engineering. The
company initially provided add-on boards for the MITS
Altair 8800 microcomputer.
SwyftCard is a card developed for the Apple II
computer by Jef Raskin at Information Appliance Inc., in
the early 1980 ' s. It facilitated a number of convenient
operations such as printing, calculations,
telecommunications and sold for $89.95.
Vector Graphic is a company operated by Lore Harp
and Carol Elly. They manufactured memory and other
boards in the late 1970' s. The boards were designed by
IBM PC Cards
Tecmar, Inc. is a company founded by Martin A.
Alpert around 1974, that provided add-on cards for the
IBM Personal Computer.
In April 1982 the Xedex Corporation announced the
Z-80 coprocessor card named "Baby Blue" for the IBM
Personal Computer. The card had a Z-80B microprocessor
that enabled CP/M programs to be run on an IBM PC.
Some other suppliers were: Quadram' s Quadboard,
which provided a clock, 64K bytes of additional memory,
parallel and serial ports for $595 and the AST Research
17.7 ... Modems
The modem was invented by AT&T in 1960 and one of
the earliest hobby modems called the Pennywhistle was
described in the March 1976 issue of Popular
Paul Collard, Casey G. Cowell and Steve Muka
founded the U.S. Robotics Corporation in 1975. The first
product was an acoustic coupler followed by modems. U.S.
17/20 PartV Bits and Bytes
Robotics became a public company in 1991 and was
acquired by the 3Com Corporation in 1997.
Dennis C. Hayes and partner Dale Heatherington
founded D.C. Hayes Associates Inc., in January of 1978.
The company name changed later to the Hayes
Microcomputer Products Inc., then to the Hayes
Corporation. Although modems were common in the business
world, Hayes was an early commercial developer of modems
for microcomputers. Hayes introduced the 80-103A Data
Communications Adapter modem for professional and hobby
communicators in April 1978 . The unit was priced at
$49.95 for a bare board and $279.95 assembled. The
Micromodem 100 was introduced for S-100 bus
microcomputers in 1979. It could transmit data at 110 to
300 bbs and had a price of $399. In mid 1981 the
Smartmodem 300 was released. Hayes also developed
software to facilitate the transfer of information by
modem on a phone line .
In late 1979, a company called Novation, Inc.,
introduced the CAT acoustic modem that was advertised at
a price of "less than $199."
The VICMODEM was introduced by Commodore in March
1982 for use with the VIC computer. An interface program
named VICTERM was included with the unit . The modem was
priced at only $109.95 and included free offers from
CompuServe, Dow Jones News and The Source.
17.8 ... Miscellaneous
A bus system is a set of hardware connections
used for power, signal and data transfer between
components of a computer system. The bus system is
characterized by its size, such as 8-bit or 16-bit and
the number of lines or connection points . One of the
earliest bus systems for a personal computer was the
Altair Bus developed by MITS, Inc., for the Altair 8800
in January 1975. Other manufacturers adapted this bus
and it became known as the S-10 Bus.
Subsequently the IEEE established a standard for
the S-100 Bus. Then a working group of the IEEE Computer
Hardware and Peripherals 17/21
Society developed the IEEE 696 bus standard. It is an
augmentation and extension of the S-100 bus to 16 bits
Southwest Technical Products Corporation (SwTPC)
developed the SS-50 bus for the SwTPC 6800 Computer
System that they released in November 1975. It was used
by a number of other manufacturers in computers using
the Motorola 6800 microprocessor, such as the Smoke
Signal Broadcasting Chieftain and the Gimix Ghost.
The release of the IBM Personal Computer in
August 1981 established another new bus standard, the PC
Bus. This was an 8-bit bus with 62 connection lines. IBM
then added additional connection lines to the bus with
the release of the 16-bit AT computer in August 1984.
The AT Bus subseguently became known as the Industry
Standard Architecture (ISA) bus.
Micro Channel Architecture (MCA) is a proprietary
32-bit multitasking bus architecture of IBM. It was a
design feature of the Personal System/2 (PS/2) family of
computers that were released by IBM in April 1987.
The Extended Industry Standard Architecture
(EISA) was developed by a consortium of nine companies:
AST Research, Compag, Epson, Hewlett-Packard, NEC,
Olivetti, Tandy, Wyse and Zenith and was announced in
September 1988. It was developed as an alternative to
the IBM MCA (Micro Channel Architecture) bus used on the
PS/2 computers and provided some of the MCA features.
EISA has a 32-bit data path and maintained compatibility
with the earlier ISA architecture.
NuBus is a high-performance expansion bus used in
the Apple Macintosh computer that was developed at the
Massachusetts Institute of Technology (MIT) . SCSI (Small
Computer System Interface) that is pronounced "scuzzi,"
is an input output bus that provides a high-speed
interface for connecting personal computers to
peripheral devices. The VL Bus is a design established
by the Video Electronics Standards Association (VESA) in
17/22 PartV Bits and Bytes
The first digitizer was called the Bit Pad with a
11-inch active area and was advertised by the
Summagraphics Corporation in November 1977. The unit had
a price of $555 .
Development of the floppy disk drive by IBM in
1971, created a reguirement for floppy disks.
Significant suppliers of floppy-disks were 3M, Dysan,
Elephant, IBM, ITC (later Verbatim) , Maxell, Memorex,
Sony and Xidex.
Information Terminals Corporation (ITC), a
dominant supplier of digital data cassettes, obtained a
license from IBM to manufacture 8-inch floppy disks in
June 1973. The company produced its first floppy disks
in December and became a dominant supplier of floppy
disks. ITC collaborated with Shugart Associates to
provide disks for the new 5.25-inch disk drive
introduced in December 1976. The single-sided, single-
density disks had a storage capacity of 180 kilobytes.
Then in July 1978, ITC introduced a 720 kilobyte double-
sided, double-density disk. The company name changed to
Verbatim Corporation in 1978. Between 1979 and 1980
Verbatim had severe and costly guality problems . A
license was obtained from the Sony Corporation to
manufacture 3.5-inch diameter hard plastic case
microdisks in the spring of 1983. Verbatim also
introduced a high-density minidisk with a storage
capacity of 1.2 megabytes in 1983 and increased it to
1.44 megabytes in 198 6.
Between 1984 and 1985, Verbatim started
encountering significant financial difficulties due to
increasing competition and falling prices for disks.
This resulted in the company being purchased by the
Eastman Kodak company in June 1985 for $175 million. But
by 1990, Kodak was also having problems and sold
Verbatim to Mitsubishi Kasei, a large diversified
Japanese company in May. Mitsubishi Kasei changed its
name to Mitsubishi Chemical Company in October 1984.
Verbatim is still a dominant supplier in the floppy disk
Hardware and Peripherals 17/23
An article entitled "A Short History of the
Keyboard" in the November 1982 issue of Byte magazine
describes variations in keyboard layouts.
Another article entitled "Keyboard Karma" in
DIGITAL DELI [190, pages 267-269] describes the problems
the Japanese have with keyboards.
Microsoft introduced a new ergonomic Natural
Keyboard in 1994.
The mouse concept was invented by Douglas C.
Engelbart at the Stanford Research Institute in 1964.
Roger Bates and William K. English assisted in the
development. The first public demonstration was at the
ACM/IEEE Fall Joint Computer Conference in December
1968. Engelbart ' s mouse was an analog device with a
wooden housing that contained a button (subseguently
three buttons) and wheels that rotated two
potentiometers. The potentiometers converted the
movement of the mouse on a surface into electrical
signals that controlled the position of the cursor on a
terminal screen. The buttons were used for selection and
to enter commands .
A digital wheeled type of mouse was developed by
Jack Hawley for the Alto research computer at the Xerox
PARC (Palo Alto Research Center) in 1972. Also at PARC
in 1972, Ronald Rider developed the ball type of mouse
that was subseguently changed by Hawley to improve its
The first commercial implementations were on the
Xerox Star in 1981, and on the Apple Lisa and Macintosh
computers in 1983 and 1984 respectively. The Xerox Star
digital mouse used two buttons for control purposes.
Apple Computer designed a new digital mouse for the Lisa
computer that used a rubber ball with optical scanners
to detect motion and one button for control purposes. A
degree of controversy exists regarding the number of
buttons to include on a mouse. Human factor studies to
determine the simplest operation, tend to favor a two
17/24 PartV Bits and Bytes
A company called Mouse Systems introduced the
first commercial mouse for the IBM Personal Computer in
1982. It was a three-button mouse.
Microsoft introduced a mouse with an add-on card
for the IBM Personal Computer and a mouse for any MS-DOS
computer using the serial port in May 1983 (see Section
12.1) . It was priced at $195 with interface software. A
new design resembling a bar of soap was released in
September 1987. In late 1996, Microsoft announced the
Intellimouse priced at $85. The principal new feature of
the Intellimouse was an additional miniature wheel
located between the left and right buttons that could be
used for scrolling in application programs.